Many products used in manufacturing are transported in containers or drums. The product must be removed from the container during the manufacturing process. The most common method of removing the product from the container is by inverting the container, allowing gravity to cause the product to flow from the container. Some products, such as liquids or free-flowing solids, easily flow from the container and therefore do not require being fully inverted to empty the container. Other products, such as powders, do not flow freely and require the container to be fully inverted 180 degrees to completely empty the container.
A common existing mechanism used to invert containers employs a single cam roller and cam track to cause the container to invert as the container is raised. This mechanism is not capable of fully inverting the container 180 degrees due to limitations of the single cam roller. Therefore, this mechanism can only be employed for free-flowing products that do not require the container to be fully inverted 180 degrees.
Fully inverting a container 180 degrees is commonly achieved with the use of a hydraulic rotary actuator. The hydraulic rotary actuator is a rack and pinion type device that also provides motion control as the container's center of gravity goes past the axis of rotation, referred to as “over-centering”. The hydraulic rotary actuator requires the use of hydraulic fluid for motion control as hydraulic fluid is non-compressible.
The use of hydraulic systems often presents a quality control issue due to the potential for product contamination with hydraulic fluid, as in the food and pharmaceutical industries. Yet there are many applications, particularly in the pharmaceutical industry, where it is necessary for the containers to be fully inverted 180 degrees in order to completely empty the container.